JS implements text automatically' to google search box

Note: If you use it alone, you cannot appear on the same page with the included search and login. There is no error when opening the page. Just a little aaa, etc. There will be errors on the web page. My solution is to prevent them from appearing on the same page, but this is inconvenient. Can you define val or other methods to solve this problem? Please give me some advice! Thanks
[0] refers to the first form in the page. When there are two forms on the page, setval(val) is only valid for form[0]. The second form appears is form[1]